Field of the Invention
The present invention relates to an imprint apparatus and a method of manufacturing an article.
Description of the Related Art
The imprint technique is attracting a great deal of attention as one of nano-lithography techniques for volume production of, for example, magnetic storage media and semiconductor devices. In the imprint technique, a mold having a fine pattern formed on it is pressed against a resin supplied onto a substrate, and the resin is cured in this state. By separating the mold from the cured resin, the pattern of the mold can be transferred onto the substrate.
In the imprint technique for manufacturing, for example, a semiconductor device, it is a common practice to use a plurality of molds to form a plurality of patterns on top of each other on a substrate. Hence, in an imprint apparatus which uses this technique, it is important to overlay the pattern of a mold on that of a substrate with high accuracy, so magnification correction in which the size of a pattern formed on a mold is corrected by pressing a plurality of portions on the side surface of the mold is performed. However, since the plurality of portions on the side surface of the mold have different shapes, a force may act in a direction, different from that in which the mold is pressed, when all portions are pressed in the same manner. If such a force acts, distortion may occur in the pattern of the mold, thus making it difficult to overlay the pattern of the mold on that of the substrate with high accuracy. To prevent this problem, Japanese Patent Laid-Open No. 2010-80714 describes a method of providing a plurality of holding units which hold a plurality of portions in the outer peripheral region of the mold, and independently driving the respective holding units in a direction (Z-direction) perpendicular to the substrate surface to correct the shape of the mold in accordance with that of the substrate.
An imprint apparatus described in Japanese Patent Laid-Open No. 2010-80714 uses a plurality of holding units to hold a mold in a plurality of portions of the outer peripheral region of the mold, and independently drives the respective holding units in the Z-direction to improve the overlay accuracy. Unfortunately, in such an imprint apparatus, the respective holding portions drive the respective portions of the mold in different amounts in the Z-direction (a direction perpendicular to the substrate surface), so the mold has a complicatedly distorted shape. That is, correcting the shape of the mold in accordance with that of the substrate improves the overlay accuracy, but leads to insufficient magnification correction of the pattern formed on the mold. Therefore, to overlay the pattern of the mold on that of the substrate with high accuracy, it is necessary to perform magnification correction while efficiently suppressing distortion generated by each holding unit. Further, since magnification correction must be done with high accuracy by increasing the number of portions where forces are applied to the mold, it is necessary to simplify a mechanism which performs magnification correction.